Hydrocracking heavy hydrocarbon oils



United States Patent 3,346,482 HYDROCRACKIN G HEAVY HYDROCARBON OILS William Floyd Arey, Jr., Baton Rouge, and Ralph Burgess Mason, Denham Springs, La., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed Aug. 23, 1963, Ser. No. 304,269 17 Claims. (Cl. 208-111) This invention relates to the catalytic hydrocracking of heavy hydrocarbon oils. Particularly, it relates to a catalytic hydrocracking process wherein heavy hydrocarbon oils containing appreciable quantities of sulfur, nitrogen and/ or metal compounds are subjected to cracking in the presence of hydrogen and a catalyst comprising a crystalline alumino-silicate zeolite composited with a platinum group metal.

Hydrocracking has recently become a subject of considerable interest within the petroleum industry because of certain particularized advantages that it offers over conventional catalytic cracking operations. Chemically, hydrocracking may be thought of as a combination of hydrogenation and catalytic cracking and is effected in the presence of a suitable bifunctional catalyst capable of simultaneously cracking high boiling hydrocarbons to lower boiling fractions and hydrogenating olefinic and aromatic materials into saturated paraffins and naphthenes. Among the advantages offered by hydrocracking are the ability to selectively convert refractive heavy aromatic feeds to high quality naphtha or middle distillate, with significantly less gas and coke yield and higher quality liquid products than are usually produced by catalytic cracking; and the adjustability of hydrocracking selectivity to produce a wide range of liquid products, e.g. gasoline, middle distillate, etc.

Generally, hydrocracking finds its highest degree of utility in the cracking of hydrocarbons boiling in the heavy naphtha and light gas oil range. It has however met with only limited acceptance in the upgrading of heavy hydrocarbon oils, particularly those containing high boiling components having substantial sulfur and nitrogen contents such as total crude oil, topped crudes and residua, shale oil, coal tars, etc. The various sulfur and nitrogen compounds present in such oils tend to poison the hydrocracking catalyst and to deposit coke during the hydrocracking operation. It has been particularly found that the higher boiling petroleum fractions of such oils, ie those fractions boiling above about 750 F., and particularly above about 850 F., contain relatively high proportions of the above-mentioned objectionable contaminating materials. Accordingly, conventional hydrocracking of such fractions, or of oil feeds containing such fractions, has proved to be of very limited effectiveness.

It will be appreciated, therefore, that there is presently a high incentive for discovering a successful means for hydrocracking heavy hydrocarbon oil feeds containing high boiling petroleum fractions to valuable lower boiling products of commercially acceptable quality. It is accordingly the purpose of the present invention to provide an improved process for hydrocracking such feeds, which process involves the use of a recently discovered hydrocracking catalyst, the composition of which is critically controlled within prescribed limits.

The aforementioned hydrocracking catalyst comprises a crystalline alumino-silicate zeolite having a platinum group metal deposited thereon or incorporated therein. Prior to the discovery of this hydrocracking catalyst,

various conventional catalysts, such as the oxides or sulfides of iron group metals supported on amorphous silica or silica-alumina, had been found to be extremely sensitive to the presence of feed impurities, and especially to organic nitrogen compounds. Under such conditions these conventional catalysts exhibited low activity and additiona-lly required either frequent regenerations or the usev of non-optimum reaction conditions which were not capable of producing maximum yield and quality of desired product. However, with the advent of the aforementioned platinum group metal on crystalline zeolite hydrocracking catalyst, the various difliculties experienced with the prior art catalysts were found to be substantially lessened in the hydrocracking of conventional feeds, e.g. feeds having nitrogen contents up to about 500 ppm. and boiling between about 400 and 700 F., (or 300 ppm. for higher boiling feeds) such as thermal and catalytic heating oils, light virgin gas oils, etc. Thus, excellent yields of lower boiling hydrocarbons, e.g. gasoline, were obtained with minimum coke-forming tendency, the required frequency of regenerations was substantially reduced, and relatively mild reaction conditions were utilizable without extensive feed pretreatment, e.g. removal of nitrogen, as was usually required prior to contact with the conventional catalysts. However, in the hydrocracking of the aforementioned hydrocarbon oil feeds containing high boiling components and contaminants, even these highly superior zeolite catalysts have proved relatively ineffective in producing an acceptable degree of conversion to lower boil ing products of desired quality.

The present invention is concerned with the discovery that the proportion of platinum group metal contained by or composited with the crystalline zeolite component is highly critical in determining the successful conversion of heavy petroleum feeds. As will be hereinafter discussed, it 'has been unexpectedly discovered that a high degree of conversion may be achieved by increasing the proportion of platinum group metal contained in the crystalline zeolite. While the range of operable proportions of the platinum group metal may fall within the general ranges suggested by the prior art, it should be emphasized that the present invention is not directed to the conversion of petroleum oils generally, but to hydrocarbon oil feeds containing high boiling petroleum fractions specifically, which feeds will be hereinafter fully described. Thus, both the nature of the hydrocarbon oil feed and the composition of the hydrocracking catalyst are regarded as critical in determining the successful operation of the process of the present invention.

In accordance with the present invention, hydrocracking is accomplished in the presence of hydrogen and catalyst at temperatures of from about 550 F to about 850 F., preferably 675 to 775 F.; pressures of from about 500 to about 3,000 p.s.i.g., preferably 1,500 to 2,000 p.s.i.g.; liquid hourly space velocities of from about 0.1 to about 10, preferably 0.5 to 2.5, volumes of feed per volume of catalyst per hour; and hydrogen rates of from about 2,000 to about 20,000, preferably 6,000 to 12,000, standard cubic feet (s.c.f.) per barrel of feed. The conversion expressed as volume percent conversion to products boiling below about 430 F will generally be maintained at about 30 to preferably 50 to 60%, although other levels may be readily employed. A fixed, moving, or fluidized bed reactor may be employed.

The hydrocarbon oil feeds contemplated for use in the process of the present invention include total crude oils, topped crude oils, visbroken petroleum residua, shale oil,

coal tar, etc. Such feeds are characterized by their relatively high total nitrogen contents, their high boiling constituents and particularly by the high nitrogen contents of the high boiling fractions contained therein. Specifically, these hydrocharbon oil feeds contain between about 100 and about 20,000 ppm. total nitrogen; and at least about 20 vol. percent, e.g. 20 to 100 vol. percent, of a petroleum fraction having a initial boiling point at least about 650 F., preferably at least about 800 F., said fraction containing at least about 500 p.p.m., preferably 600 to 5,000 p.p.m., nitrogen. Among the feeds most preferably utilized are total or reduced crudes (atmospheric residua) containing about 2 to 40 vol. percent, of a petroleum fraction boiling above about 1,000 E, said fraction containing at least about 2,000 ppm. nitrogen. These heavy oils may also be characterized by their specific gravities, sulfur contents, Conradson carbon residues, etc. However, because of the wide variance of these properties in the hydrocarbon feeds contemplated, it will be most meaningful to utilize the foregoing description, as the nitrogen content and the boiling range (or molecular weight) of the nitrogen-containing fractions are determinative factors in their susceptibility to hydrocracking. By way of illustration, typical heavy hydrocarbon oils may have specific gravities of about 1 to 40 API, sulfur contents of 0.1 to 5 wt. percent and Conradson carbon residues of 0.5 to 20 wt. percent.

The hydrocracking catalyst utilized for the conversion of the aforementioned hydrocarbon oil feeds comprises a crystalline metallic alumino-silicate zeolite, Well known in the art as a molecular sieve, having a platinum group metal (e.g. palladium) deposited thereon or composited therewith. These crystalline zeolites are characterized by their highly ordered crystalline structure and uniformly dimensioned pores, and have an alumino-silicate anionic cage structure wherein alumina and silica tetrahedra are intimately connected to each other so as to provide a large number of active sites, with the uniform pore openings facilitating entry of certain molecular structures. It has been found that crystalline aluminosilicate zeolites, having effective pore diameter of about 6 to 15, preferably 8 to 15 Angstrom units, when composited with the platinum group metal, and paritcularly after base exchange to reduce the alkali metal oxide (e.g. Na O) content of the zeolite to less than about 10 wt. percent, are effective hydrocracking catalysts, particularly for the hydrocarbon oil feeds herein contemplated. The size of the pore openings is regarded as critical since smaller openings, e.g. 4 A., will not be large enough to allow entry of certain heavy hydrocarbon molecules such as branched chain paraffins, cyclic compounds, etc. Additionally, the crystalline nature of the catalyst is important, since it determines the uniformity of the pore openings.

Naturally-occurring large pore crystalline alumino-silicate zeolites may be exemplified by the mineral faujasite which may be beneficially employed. Synthetically produced alumino-silicate zeolites having large pore diameters, such as synthetic faujasite and synthetic mordenite, are also available and will be preferred in the present invention. In general, all crystalline alimino-silicate zeolites, in natural or synthetic form, contain a substantial portion of an alkali metal oxide, normally sodium oxide.

More specifically, the support for the hydrocracking catalyst used in the present invention is a crystalline alumino-silicate zeolite having an effective pore diameter of about 6 to A., preferably 8 to 15 A., wherein a substantial portion of the alkali metal, e.g. sodium, has been replaced with a cation (either a metal cation or a hydrogen-containing cation, e.g. NH so as to reduce the alkali metal oxide (e.g. Na O) content to less than 10 wt. percent and preferably to about 1 to 5 wt. percent (based on zeolite). The anhydrous form of the baseexchanged large pore crystalline alumino-silicate zeolite prior to compositing with platinum group metal may be generally expressed in terms of moles by the formula:

wherein Me is selected from the group consisting of hydrogen and metal cations (so that the alkali metal oxide content is less than 10 wt. percent of the zeolite), n is its valence and X is a number from 2.5 to 14, preferably 3 to 10 and most preefrably 4 to 6. Crystalline zeolites having these silica to alumina ratios have been found to be highly active, selective and stable.

As hereinbefore mentioned, it has been found that the proportion of platinum group metal contained in the final hydrocracking catalyst is critical in the successful hydrocracking of heavy oil feeds. (The term platinum group metal is intended to include platinum, palladium, osmium, ruthenium, rhodium, iridium, etc.). Specifically, it has now been discovered that the final catalyst should contain at least about 1.0 wt. percent, preferably at least about 2.0 Wt. percent, platinum group metal based on the weight of the final catalyst, in order to successfully hydrocrack heavy oil feeds. Preferred ranges will be about 1 to about 10 wt. percent, more preferably about 2 to about 5 wt. percent, and most preferably 2 to 3 wt. percent. It has been found that catalysts containing proportions of platinum group metal below these ranges, i.e. below about 10 wt. percent, are generally incapable of effectively converting the hydrocarbon oil feeds contemplated by the present invention.

Upon consideration of the prior art experience with hydrocracking catalysts in general, and the zeolite catalysts in particular, the effect of platinum group metal content on the degree of hydrocracking conversion obtained is particularly unexpected. Heretofore, it had been generally understood that the platinum group metal served merely as a hydrogenation component, and that the actual cracking of the larger molecules was accomplished primarily by the cracking component of the catalyst, e.g. an amorphous silica-alumina support, a crystalline alumino-silicate zeolite support, etc. Therefore, an increase in the proportion of platinum group metal might only be expected to produce a greater degree of hydrogeneration, rather than any significant change in the degree of cracking. However, contrary to these expectations, it has now been found that an increase in the platinum group metal content of the crystalline aluminosilicate zeolite catalysts will substantially alter their cracking ability when used in the hydrocracking of heavy oil feeds. It should again be emphasized that this discovery applies only to the hydrocarbon oil feeds hereinbefore described, and that with conventional feeds having relatively low nitrogen contents, the surprising effects of platinum group metal content on hydrocracking performance is not observed.

The processes for synthetically producing the crystalline alumino-silicate zeolite component of the hydrocracking catalyst herein contemplated are well known in the art. They involve crystallization from reaction mixtures containing: A1 0 as sodium aluminate, alumina sol and the like; SiO as sodium silicate and/ or silica gel and/or silica sol; and metal oxide as alkaline hydroxide, preferably sodium hydroxide, either free or in combination with the above components. Careful control is kept over the metal oxide (e.g. Na O) concentration of the mixture, as well as the proportions of silica to alumina and soda (metal oxide) to silica, the crystallization period, etc., to obtain the desired product. A typical procedure for producing crystalline alumino-silicate zeolite having a silica to alumina mole ratio of about 4 to 6 would be as follows:

Colloidal silica is mixed with a solution of sodium hydroxide and sodium aluminate at ambient temperature to d produce a reaction mixture having the following molar ratios of reactants:

Reactants: Molar ratio Nazolsloz t Slog/A1203 8 to H O/Na O 20 to 60 The reaction mixture may then be allowed to digest at ambient temperatures for periods of up to 40 hours or more in order to aid crystallization, after which period it is heated at 180 to 250 F., e.g. 200 to 220 F., for a sufiicient time to crystallize the product, e.g. 24 to 200 hours or more. The crystalline, metallo alumino-silicate is separated from the aqueous mother liquor by decantation or filtration and washed to recover a crystalline product.

The zeolite is then base-exchanged with a hydrogencontaining or metal cation to reduce the Na O content to below wt. percent. Suitable metal cations include ions of metals in Groups LE to VIII and rare earth metals, and preferably metals in Groups II, III, VIII, and rare earth metals. Where a hydrogen-containing cation is used to replace the sodium, the hydrogen form of the zeolite is produced. A convenient method of preparing the hydrogen or decationized form is to subject the zeolite to base-exchange with an ammonium cation solution followed by controlled heating at elevated tempera ture, e.g. 600 to 1,000 F., to drive off ammonia and Water. Alternatively, the ammonium form of the zeolite can be used.

The base-exchanged zeolite is composited or impregnated with platinum group metal by treatment (e.g. wet impregnation or base-exchange) with a platinum or palladium salt or ammonium complex, e.g. ammonium chloroplatinate, palladium chloride, etc. For example, a suitable palladium catalyst may be prepared by simply slurrying the desired quantity of the ammonium form of the zeolite in water, subsequently adding an ammoniacal palladium solution having the desired quantity of palladium, and mixing the resulting slurry for a short period of time at ambient temperature. The catalyst is then preferably subjected to calcination at elevated temperatures, e.g. about 500 to 1500 F.

The above-described catalyst is most preferably used in the hydrogen or ammonium form wherein the sodium content of the sieve has been reduced with either hydrogen ion or ammonium ion. However, under certain circumstances, it may be desirable to replace the sodium by other elements such as cobalt, nickel, zinc, magnesium, calcium, copper, or barium.

The invention will be further illustrated by reference to the following examples, which are not intended to be limiting.

EXAMPLE 1 Part A.Preparati0n of hydrocracking catalyst containing 2.0 wt. percent palladium A crystalline alumino-silicate zeolite having a silica to alumina mole ratio of 5.3 to 1 was prepared by the following procedure. A slurry mixture of 1,655 grams of commercial sodium aluminate containing 65 wt. percent NaAlO and 5,300 grams of sodium hydroxide (97% NaOH), contained in 37 pounds of water, was added with rapid stirring to 78.5 pounds of a commercially available colloidal silica sol containing 30 Wt. percent silica (Ludox solution, supplied by E. I. du Pont de Nemours & Co. Inc). Mixing was conducted at ambient temperature of 75 F. The total relative molar composition of the resultant reaction mixture was as follows:

27 Nazoil H2O Stirring was continued to form a homogeneous mixture and the composite slurry was then kept at ambient temperature, in an open vessel, with stirring for a digestion period of about 2 hours, after which time it was heated to 212 F. The vessel was then sealed and heated at 212 F. for 6 days, which was the point of maximum crystallinity as determined by periodic sampling and analysis. The vessel was then cooled and opened, and the crystalline slurry was filtered, washed with water, and oven dried at 275 F. A sample of the crystals was calcined for 4 hours at 850 F. and analyzed to show the following composition:

64.8 Wt. percent Si0 14.0 wt. percent Na O, and 20.9 wt. percent A1 0 which corresponds to an approximate molar composition of about 1.1 Na O:Al O :5.3 SiO Five pounds of the above product crystals were then ion-exchanged at room temperature with 7.5 gallons of a 19 Wt. percent aqueous solution of ammonium chloride solution. The composite solution was stirred intermittently over about a 2-hour period at room temperature and the solids were then filtered. This ion-exchange procedure was repeated with fresh solution five times at a temperature of about 150 F. After the final treatment the filter cake was Water washed to substantially remove excess chloride ion.

The resulting ammonium form of the zeolite was separated by filtration and treated with a solution containing the ammonium complex of palladium chloride in an amount sufficient to produce a 2 wt. percent palladium catalyst. Specifically, an ammoniacal palladium solution having a palladium content of 0.0504 grams of palladium per cc. was prepared by dissolving palladium chloride in aqueous ammonium hydroxide. 1702 cc. of this ammoniacal palladium solution was added to a water slurry of the ammonium form of zeolite which contained 8193 grams of zeolite and had a solids content of 52.2 wt. percent. This was equivalent to about 0.4 cc. of palladium solution per gram of solids in the zeolite slurry. The composite mixture was stirred for 1 hour, filtered, water washed, dried in an oven at 212 F., and finally calcined at 1000 F.

Part B.Preparation of comparison catalyst containing 0.5 wt. percent palladium A 0.5 wt. percent palladium catalyst was prepared by essentially the same procedure of Part A of this example, except that the ammoniacal palladium solution contained 0.0126 grams of palladium per cc., which corresponded to 0.1 cc. of palladium solution per gram of solids in the zeolite slurry.

The compositions of the catalysts prepared in Part A an;1 Part B of this example are shown in the following ta e:

0.5 Wt. Percent 2.0 Wt. Percent Palladium Catalyst Palladium Catalyst 1. 1 1. 1 74. 7 73. 5 23. 7 23. 4 0. 5 2. 0 0. 0 0.0 Surface Area, M lgram 707 581 Pore Volume, cc./gram O. 49 O. 47 Pore Diameter, A 13 13 EXAMPLE 2 Hydracracking ability of the catalysts prepared The two catalysts of Example 1, containing 0.5% palladium and 2.0% palladium respectively, were utilized for the hydrocracking of three separate feed stocks having varying nitrogen contents, in a fixed bed reactor. The first feed stock was a catalytic heating oil having a nitrogen content of 40 p.p.m.; the second feed stock was a South Louisiana crude oil having a nitrogen content of p.p.m.; and the third feed stock was a West Texas atmospheric residuum having a nitrogen content of 2300 7' ppm. The inspections of these three feed stocks are shown in the following table:

TABLE I.FEED STOCK INSPECTIONS palladium catalyst is slightly more active than the 0.5%

palladium catalyst, since the latter requires a 20 F.

Feed Catalytic Heating South Louisiana West Texas Atmos- Oil Crude pheric Residuum Gravity, API 29. 3 38.4 19. 7 Sulfur, Wt. percent- 0.4 0.14 2 Total Nitrogen, p.p.n1 40 140 2, 300 Conradson Carbon, percent 0.01 0. 8 5. Vol. percent 800 F.+ FractiolL 0 70 Nitrogen Content of 800 F.+ Fraction. 600 2,600

Distillation Distribution Vol. Nitrogen, Vol. Nitrogen, Vol. Nitrogen,

percent p.p.m. percent p.p.m. percent p.p.m.

Initial to 430 F 1 32. 0

The operating conditions and conversion obtained for the hydrocracking runs with the catalytic heating oil are shown in the following table:

higher temperature to achieve approximately the same conversion.

Part B.S0uth Louisiana crude oil Similar hydrocracking runs were performed for both the high and low palladium content catalysts using the South Louisiana crude oil which contained 140 p.p.m. total nitrogen, with 600 ppm. nitrogen contained in the TABLE II.I-IYDROCRACKING OF CATALYTIC HEATING OIL Catalyst Composition 0.5% Palladium 2.0% Palladium Run Number 1 2 3 4 5 6 7 8 Operating Conditions:

Pressure, p.s.i.g 1,500 1, 500 1, 500 1, 500 1, 500 1,500 1, 500 1, 500 H Rate, s.c.f./b 6,000 6, 000 6,000 6,000 6,000 6,000 6, 000 6,000 Space Velocity, V./v./hr. 1. 1. 1. 55 1. 48 1. 58 1. 47 1. 52 1. 58 Temperature, F 663 676 676 682 647 652 652 665 Catalyst Age, hours on feed 269 245 221 321 173 244 220 297 Conversion: Vol. percent, 430 FA to 430 F. 45 56 84 46 55 58 95 800 F.+ fractions. The operating conditions, convera sions, and yields obtained for these runs are shown in the following table:

TABLE III.-HYDROCRACKING OF SOUTH LOUISIANA CRUDE Catalyst Composition 2.0% Palladium 0.5% Palladium Run Number 9 10 11 12 13 14 15 16 Operating Conditions:

Pressure, p.s.i.g 1, 500 1, 500 1, 500 1, 500 1, 500 1, 500 1, 500 1, 500

Hz Rate, s.c.f./b 11, 000 16, 000 14, 000 5, 000 9,000 18, 000 15, 000 17, 000

Space Velocity, v./v./hr 0.9 0. 1.0 1. 6 1. 0. 1.0 1. 0

Temperature, F 650 621 675 650 625 625 675 670 Catalyst Age, hours on feed 204 408 431 205 304 328 352 386 Conversion: Vol. percent 430 Fi to 430 52 40 71 4 0 0 0 0 Yields, Percent on Feed:

Dry Gas, Wt. Percent 0. 6 0.6

04, Vol. Percent 5 5 Cal430 F., Vol., Percent 69 58 430/650" F., Vol. Percent 16 22 650/850 F., Vol. Percent 6 9 850 F.+, V01. Percent 10 11 ing oil feed containing 40 ppm. nitrogen, except for the temperature required to obtain equivalent conversion. Thus, comparisons of Runs 1 to 4 and 5 to 8 indicate that equivalent conversions of 430 F.+ material to lower boiling material were obtained for both catalysts, but that approximately a 20 F. higher temperature was required for the 0.5% palladium catalyst. It may be concluded As indicated, the hydrocracking behavior of the two catalysts, when used with the higher nitrogen-containing South Louisiana crude oil feed was markedly different than that observed with the low nitrogen content catalytic heating oil feed (Table I). Thus, over about the same range of operating conditions, the 0.5 palladium catalyst produced essentially no conversion, Whereas the 2% palladium catalyst produced substantial conversion, with that with a low nitrogen content feed stock, the 2% good yield of the desired C /43O" F.fracti0n.

Part C.Wst Texas atmospheric residuum silica to alumina mol ratio of 3 to 10 and pore openings of about 8 to Angstrom units.

4. The process of claim 1, wherein said hydrocracking conditions include a temperature of from about 550 F. to about 850 F., a pressure of from about 500 to about 3000 p.s.i.g., a liquid hourly space velocity of from about 0.1 to about 10 volumes of feed per volume of catalyst per hour, and a hydrogen gas rate of from about 2000 to about 20,000 standard cubic feet per barrel of feed.

5. The process of claim 1, wherein said zeolite is composited with at least about 2.0 wt. percent platinum group metal.

TABLE IV.HYDROCRACKING OF WEST TEXAS ATMOSPHERIC RESIDUUM Crystalline Zeolite Catalyst 2% Palladium on Catalyst Composition 2.0% Palladium 0.5% Palladium Amorphous Silica-alumina Operating Conditions:

Yields, percent on Feed:

Dry Gas, Wt. Percent 3 0 Vol. percent C5/430 F., Vol. percen 430 F.+, Vol. percent 2o Nil 2 As shown in the above table, the 2% palladium catalyst again successfully converted the extremely high nitrogen content West Texas atmospheric residuum feed, which contained an overall nitrogen content of 2300 p.p.m., and an 800 F.+ fraction containing 2600 ppm. nitrogen. A 50% conversion and 52% yield of the desired C /430 F. fraction was obtained for the 2% catalyst even after 230 hours on feed, as compared to essentially no conversion for the 0.5% catalyst after only 20 hours on feed. The remarkable effect of the palladium content of the catalyst is once again demonstrated.

The ineflicacy of the amorphous catalyst is additionally demonstrated. At comparable operating conditions and palladium content, and low catalyst age, the amorphous catalyst produced only a 2% conversion to 430 F. products.

It may be concluded from the above data that heavy nitrogen-containing oil feeds, which heretofore have not been susceptible to successful hydrocracking, may now be converted to valuable lower boiling products by means of the process of the present invention, which process involves the utilization of a hydrocracking catalyst comprising a crystalline alumino-silicate zeolite containing at least about 1.0 wt. percent, preferably at least about 2.0 wt. percent, of a platinum group metal, e.g. palladium.

What is claimed is:

1. A process for hydrocracking a heavy hydrocarbon oil feed to obtain lower boiling product, said feed having a nitrogen content between about 100 and about 20,000 p.p.m. and containing about 20 to .100 volume percent of a petroleum fraction having an initial boiling point of at least about 650 F. and a nitrogen content of at least about 500 ppm. which process comprises subjecting said feed to hydrocracking conditions in the presence of added hydrogen and a hydrocracking catalyst comprising a crystalline alumino-silicate zeolite composited with at least about 1.0 wt. percent platinum group metal, said zeolite having pore openings of about 6 to 15 Angstrom units and a silica to alumina mol ratio of 2.5 to 14, and containing less than about 10 wt. percent Na O.

2. The process of claim 1, wherein said zeolite has been base exchanged with a hydrogen-containing cation to reduce its Na O content to less than about 10 wt. percent.

3. The process of claim 1, wherein said zeolite has a 6. The process of claim 1, wherein said zeolite is composited with about 2 to 5 wt. percent platinum group metal.

7. The process of claim 1, wherein said hydrocarbon oil feed contains about 20 to volume percent of a petroleum fraction having an initial boiling point of at least about 800 F., said fraction containing 600 to 5000 p.p.m. nitrogen.

8. A process for hydrocracking a heavy hydrocarbon oil feed to obtain lower boiling product, said feed having a nitrogen content between about 100 and about 20,000 ppm. and containing about 2 to 40 volume percent of a petroleum fraction boiling above about 1000 F. and having a nitrogen content of at least about 2000 p.p.m., which process comprises contacting said feed with a hydrocracking catalyst in the presence of hydrogen at a temperature of from about 550 F. to about 850 F., a pressure of from about 500 to about 3000 p.s.i.g., a liquid hourly space velocity of from about 0.1 to about 10 volumes of feed per volume of catalyst per hour, and a hydrogen gas rate of from about 2000 to about 20,000 standard cubic feet per barrel of feed, wherein said hydrocracking catalyst comprises a crystalline alumino-silicate zeolite composited with about 2 to 5 wt. percent platinum group metal, said zeolite having pore openings of about 6 to 15 Angstrom units and a silica to alumina mol ratio of 3 to 10, and containing less than about 10 wt. percent Na O.

9. The process of claim 8, wherein said zeolite is composited with 2 to 3 wt. percent palladium and has pore openings of 8 to 15 Angstrom units and a silica to alumina mol ratio of 4 to 6.

10. The process of claim 8, wherein said temperature is between 675 F. and 775 F., said pressure is between 1500 and 2000 p.s.i.g., said space velocity is between 0.5 and 2.5 v./v./hr., and said hydrogen rate is between 6000 and 12,000 s.c.f. per barrel.

11. A process for hydrocracking an atmospheric residuum feed to obtain lower boiling product, said atmospheric residuum containing about 2 to 40 volume percent of a petroleum fraction boiling above about 1000 F., said fraction having a nitrogen content of at least about 2000 p.p.m., which process comprises contacting said feed with a hydrocracking catalyst in the presence of hydrogen and at hydrocracking conditions, said hydrocracking catalyst comprising a crystalline alumino-silicatev zeolite composited with at least about 1.0 wt. percent platinum group metal, said zeolite having pore openings of between about 6 and 15 Angstrom units and containing less than about 10 wt. percent alkali metal oxide.

12. The process of claim 11, wherein the platinum group metal content of said zeolite is about 1 to 10 wt. percent.

13. The process of claim 11, wherein the platinum group metal content of said zeolite is about 2 to 5 wt. percent.

14. The process of claim 11, wherein the platinum group metal content of said zeolite is about 2 to 3 wt. percent.

15. The process of claim 11, wherein said hydrocracking conditions include a temperature of from about 550 F. to about 850 F., a pressure of from about 500 to about 3000 p.s.i.g., a liquid hourly space velocity of from about 0.1 to about 10 volumes of feed per volume of catalyst per hour, and a hydrogen gas rate of from about 2000 to about 20,000 standard cubic feet per barrel of feed.

References Cited UNITED STATES PATENTS 2,971,904 2/11961 Gladrow et a1 208138 2,983,670 5/1961 Seubold 208-111 3,119,763 l/ l96'4 Haas et al. 208-110 DELBERT E. GANTZ, Primary Examiner.

ALPHONSO D. SULLIVAN, Examiner.

ABRAHAM RIMENS, Assistant Examiner. 

1. A PROCESS FOR HYDROCRACKING A HEAVY HYDROCARBON OIL FEED TO OBTAIN LOWER BOILING PRODUCT, SAID FEED HAVING A NITROGEN CONTENT BETWEEN ABOUT 100 AND ABOUT 20,000 P.P.M. AND CONTAINING ABOUT 20 TO 100 VOLUME PERCENT OF A PETROLEUM FRACTION HAVING AN INITIAL BOILING POINT OF AT LEAST ABOUT 650*F. AND A NITROGEN CONTENT OF AT LEAST ABOUT 500 P.P.M. WHICH PROCESS COMPRISES SUBJECTING SAID FEED TO HYDROCRACKING CONDITIONS IN THE PRESENCE OF ADDED HYDROGEN AND A HYDROCRACKING CATALYST COMPRISING A CRYSTALLINE ALUMINO-SILICATE ZEOLITE COMPOSITED WITH AT LEAST ABOUT 1.0 WT. PERCENT PLATINUM GROUP METAL, SAID ZEOLITE HAVING PORE OPENINGS OF ABOUT 6 TO 15 ANGSTROM UNITS AND A SILICA TO ALUMINA MOL RATIO OF 2.5 TO 14, AND CONTAINING LESS THAN ABOUT 10 WT. PERCENT NA2O. 